Deep Reviews: We Tried the 5 Lash Serums That Deliver Visible Length and Volume

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Who doesn't want longer, thicker, and fuller lashes? Sure, the best mascaras will give you long, fanned-out lashes, but sometimes, you might want to forgo mascara altogether. Maybe you just want long lashes without the upkeep of regular and costly lash-extension appointments. Personally, I would like to optimise my lashes to look fuller, longer and all-around healthier. Enter eyelash serums, which promise all of the above.

But which ones actually work to deliver growth and healthier, more voluminous lashes? For this month's Deep Reviews, I rallied the Who What Wear UK team together to test five of the best eyelash serums that are most sought after right now, from RevitaLash to UKLash and Olaplex to The Ordinary and Beauty Pie.

What to Look For

There are different ingredients that can be found across different eyelash serums, but the two key ingredients that help to grow our eyelashes tend to be prostaglandins and peptides in most formulas. However, prostaglandin-based eyelash serums should be used with caution.

“Many lash serums contain prostaglandin analogues, which can cause increased pigmentation of the eyelid skin, leading to dark circles," says Dr Elizabeth Hawkes, consultant ophthalmic and oculoplastic surgeon. "Excessive use can even turn blue eyes brown due to pigment changes,” she says. “I do prescribe these products, but mainly for patients with genuine medical reasons who have lost their lashes. For cosmetic use, there are other safer alternatives," she says. “These compounds can also cause thinning of the skin around the eyes and fat loss, which may make the eyes appear sunken. Given how close lash serums are applied to the eye, there is also a risk of contamination and inflammation if used incorrectly. It’s crucial consumers choose formulations carefully and follow instructions to avoid complications," she adds.

If you want to avoid prostaglandins altogether, there are plenty of peptide-based eyelash serums, which work in a similar way to help boost the length of your eyelashes, but without the risks associated with prostaglandin-based formulas. Peptide lash serums are also a great choice if you have sensitive eyes, too, as they tend to be less irritating.

Best Lash Serums, Tried & Tested

• Best Overall: UKLash Eyelash Serum, £38
• Best Luxury Lash Serum: Olaplex LashBond Building Serum, £64
• Best for Thickening Lashes: Revitalash Advanced Eyelash Serum, £139
• Best for Lashes and Brows: Beauty Pie Lash Fuel, £35
• Best Affordable Lash Serum: The Ordinary Multi-Peptide Lash and Brow Serum, £14

1. UKLash Eyelash Serum 

Ingredients: Vitamin B5, green tea extract, myristoyl pentapeptide-17

Prostaglandin-free? No. However, UKLash offers two prostaglandin-free formulas: the Complex Peptide Lash Growth Serum (£42) and the Sensitive Lash Growth Serum (£38).

Rating: 9/10

From the reviews I have seen online, I was really excited and intrigued to try the UKlash eyelash serum. I am quite lucky, as I do already have quite long lashes, but I was excited to see if the serum would lengthen them even more.

I do have slightly sensitive eyes, but I had no issues applying the serum. The brush was thin and long, so it slid over my eyelashes seamlessly. I applied the serum every evening to my top lashes, except for a couple of nights when I was on holiday. It is so quick to do that it was easy to add to my bedtime routine.

The recommended time frame to see maximum results is three months, so I still have two months to go. However, I was really surprised when I started to see a change after a week! Full disclaimer: I did get my eyelashes tinted halfway through the test, so they did look slightly longer without makeup on, but it became especially obvious that they were growing when I had mascara on. When I apply my makeup, they look more voluminous and almost touch my eyebrows!

There is honestly nothing bad that I can say about this product. I'm super impressed that the serum started to show results so quickly, and the tube is really sleek with the black packaging. The price is maybe a little bit more expensive than some of the other eyelash-serum brands, but personally, I think it's worth the investment. I'd rather spend the money and know that the results are going to be worth it. After using it for a month, there is still a lot left in the tube, so I won't need to buy a new one anytime soon. Saying that, as soon as it does run out, I'll be buying it again—that's if my eyelashes aren't at the top of my eyebrows by then!

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2. Olaplex LashBond Building Serum

Ingredients: Olaplex peptide complex technology, hyaluronic acid, biotin

Prostaglandin-free? Yes

Rating: 8.5/10

If someone told me that my eyelashes would look the way they do now, I'd accuse them of lying. I am gifted with hair in every part of my body except for my eyelashes and eyebrows. I have tried everything out there to boost the growth of both, but nothing has quite done it. When shopping for mascara, you'll find me reaching for the one which promises length because that is my ultimate goal. I can't apply false lashes to save my life, so I have no choice but to rely on mascaras to achieve my desired look.

I've tried eyebrow serums but never eyelash serums, so when I heard that everyone's fave Olaplex was launching an eyelash serum, I was eager to try it. The hair on my scalp loves the brand's products, so I thought my eyelashes would too. Thanks to TikTok, I've heard a lot about eyelash serums, but I take the reviews with a grain of salt. (I'm looking at you, L'Oréal False Lash Telescopic Mascara.) I always felt people sharing their reviews were exaggerating the results, but now, I think they're right.

Now that I've tried Olaplex's LashBond Building Serum, don't be surprised if you find me on your For You page screaming its praises. I've been using the serum religiously twice a day as part of my daily skincare routine. It's pretty easy to apply. Simply use it the same way you would eyeliner—by swiping the skin along the upper lash line. On the days when I have other eye products to apply, I wait for the advised 90 seconds before following with the other products. After six weeks or so of usage, I'm already seeing results.

For best results, it's recommended to use the serum for a period of 12 weeks, but within six to seven weeks of using it, I'm already seeing results. My lashes, especially after just one coat of mascara, look much fuller and longer—so much so that my teenage daughter (who rarely compliments me) said, "Mum, are you wearing eyelash extensions?" It's amazing to see the results coming in, and I'm very happy to finally see my full lash potential.

Although this serum comes with a hefty price tag, making it one of the most expensive on the market, it also seems to be the most effective thanks to key ingredients, including the new Olaplex Peptide Complex Technology and Bond Building technology, hydrating hyaluronic acid and biotin.

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3. RevitaLash Advanced Eyelash Conditioner

Ingredients: BioPeptin Complex (which includes peptides, biotin and lipids), green tea extract, ginseng, swertia japonica, saw palmetto, amino acids and B vitamins

Prostaglandin-free? No

Rating: 7/10

When I found out that I had the chance to try the iconic RevitaLash Advanced Eyelash Conditioner, I couldn't be more excited. I had heard great things about the one-of-a-kind formula and was ready to see if the hype was real. Firstly, I'm lucky enough to have quite long lashes already, but as a blonde, they are incredibly light, meaning I rely on mascara most days. So on my eyelash journey, I was hoping to see if this serum would add some dimension to my eyelashes both pre- and post-mascara, and as I hope you can see, I was pleasantly surprised.

To come to my conclusion, I took into account a few factors. Firstly, was it easy to use? Eyes are such a delicate area, so I was very pleased to see the lightweight wand applicator, which is incredibly easy to use whether you're a makeup master or not. After removing makeup, you simply swipe the brush across the top of the lash line, and voilà! To make sure my review was completely fair, I only used it once a day as the instructions stated, and it soon became commonplace in my nighttime routine. I have to state that I did have some irritation, but I do tend to have sensitive eyes around this time of year (thanks, hay fever). Plus, I was thrilled to see RevitaLash offered a specific option for sensitive skin, ensuring all users can try it out.

Now, the important part: Does it work? Well, here's what I noticed. After about four weeks of use, I began to see slight growth in length, but most impressive was how thick and strong my lashes became. If you check out the images, you'll see that there are definitely more new lashes, especially on the outer edges of my eyes, which really help define my eye. As I mentioned, I have blonde eyelashes, and the added thickness definitely makes my lashes more defined.

I'm at the end of our test, and I can say that my lashes definitely look longer and thicker, and this serum will remain a part of my nighttime routine. However, one thing to consider is the price. At £139, it is definitely a splurge, but as you use such a small amount, this could definitely last six months or more. There are also smaller sizes that last for three months or six weeks, which makes it a little more affordable if you want to try it out first. If you're looking to invest in your lash results, then I would definitely recommend this one. Next on my list is the eyebrow conditioner!

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4. Beauty Pie Lash Fuel Advanced Peptide Serum

Ingredients: Vitamins B5, B7, panax ginseng root extract, lipo-oligopeptide, biotin, panthenol

Prostaglandin-free? Yes

Rating: 7/10

My lashes are reasonably long and dark—the plus side of having hair in abundance everywhere else(thank you, laser hair removal). That being said, they are stubbornly straight, and I wish they were a little bit longer and fuller. After an eczema breakout a couple of years ago, I lost some of the fullness along my lash line and brows, and they have never fully grown back in those areas. Additionally, my eyes are also very sensitive, and some eyelash serums that I have tried in the past have upset the skin around my eyes. So I was cautious when it came to testing. I had high hopes for Beauty Pie's Lash Fuel Advanced Peptide Serum, which promises longer lashes in two weeks and fuller lashes in four weeks (without prostaglandins) and comes with several five-star reviews on Beauty Pie's website. The serum can also be used on the brows, so I applied it there during testing as well.

I applied the serum morning and night for four weeks (I kept it on my bedside table so I wouldn't forget), and I did see a slight difference after two weeks. My lashes looked longer, and a sparse gap I had on my lower lashes was sprouting some small lashes. Result! But it was after the four-week mark that I started to see some real changes. At this point in testing, my lashes looked fuller, but they also felt incredibly healthy and glossy. They're now in the best condition they've ever been. I can see in my before-and-afters that my lashes look darker and defined, and I've also seen results on my brows, which are looking fuller and feel in better condition after having brow lamination a couple of weeks ago. I wish I could have seen more length on my lashes, but I'm confident they'll continue to lengthen with continued application.

I do have to make one criticism. It does sting my eyes a little if I apply it too heavy-handedly and it travels into my waterline, so make sure you apply it sparingly along the lash line. On the whole, I'm impressed with the results, and I think it's competitively priced at Beauty Pie's member's price of £35. I'm excited to continue using it and hopefully see further improvements to my lashes and brows.

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5. The Ordinary Multi-Peptide Lash and Brow Serum

Ingredients: Myristoyl pentapeptide-17, biotinoyl tripeptide-1, oligopeptide-2, acetyl tetrapeptide-3, caffeine, larix europaea wood extract, trifolium pratense flower extract, camellia sinensis leaf extract

Prostaglandin-free? Yes

Rating: 6.5/10

It would be remiss of me not to start this review with a disclaimer: I have very thin, very short and very pale lashes. Somehow, I missed out on my mum's gene that gave her amazing, thick, fluttery lashes, and instead, I've been left with slightly impactless ones that stick out rather than up. So it probably comes as no surprise that a lash curler and mascara are two of the most used and loved pieces in my beauty arsenal. But despite feeling like my lashes have always felt a little flat, I've actually never used a serum before. I once bought RevitaLash, but it got lost in transit, which I took as a sign to just be happy with my lot and give up on the serum search. However, fast-forward a few years later, and I was one of the first in the team to put my hand up when it came to testing out eyelash serums.

I'm a big fan of The Ordinary in general, so I was delighted to road-test the brand's lash and brow serum. It's really easy to apply, with just a quick flick of the wand along the lash line (I applied it in the mornings and evenings) being all you need. I do have quite sensitive eyes, and when the formula dripped down into them, it was quite irritating. With a few blinks and a little wash, however, the irritation was gone. It's a water-based serum, so I wasn't concerned.

When it comes to results, I think I've seen a difference. My friends and colleagues have told me my lashes look longer, but maybe because we look at our faces every day, it's hard to tell ourselves. That being said, when I put mascara on today, I definitely thought my lashes looked longer and thicker. It was probably not until the end of the first four weeks that I noticed any change, but this is in line with what the brand says to expect. I should also note that I used the serum on my brows, too, and have seen a great improvement in the thickness there already.

For the price, I think this serum is definitely worth it. It comes in at under £15, which, compared to other products on the market, is fantastic. I will definitely continue to use it, and I'm excited to see what my lashes look like in another four to eight weeks!

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How We Tested

As part of our testing criteria, each editor road-tested their lash serum for a minimum of four weeks, which is when most eyelash-serum brands state that you'll see results. You can expect to see full results after around 12 weeks of use. To find out which eyelash serums are really worth the money, we also tested lash serums across budgets to see which came out on top. As with all of our Deep Reviews, you'll find our honest and in-depth review of each product along with the team's before and after pictures of their results, both with and without mascara so you can get the full picture of the best eyelash serums in the UK right now.

How Do Lash Serums Work?

"Lash serums work in two main ways," explains Dr Sharon Wong, consultant dermatologist and co-founder of DOSE. "Some contain active ingredients that stimulate growth at the root to promote longer, thicker lashes over time, while others condition and strengthen existing lashes to make them appear fuller and healthier."

What Ingredients Help Lash Growth?

Two ingredients are known to help with lash growth. "Bimatoprost is an FDA-approved prostaglandin analogue clinically proven to promote longer, thicker, and darker lash growth," explains Dr Wong.

The second is Isopropyl Cloprostenate. "This is another commonly used prostaglandin analogue found in lash serums. Some lash growth serums also include ingredients such as peptides and hyaluronic acid to help strengthen and condition lashes, reducing breakage and supporting length retention," adds Dr Wong.

What Happens When You Stop Using Lash Serum?

If you're worried about your lashes falling out, then don't be. Dr Wong says that once you stop using a lash serum, lashes simply return to their natural appearance and condition. "Any lashes enhanced by the serum will eventually complete their normal growth cycle and shed naturally over the following months. It is therefore better to gradually reduce and wean off the use of serums rather than stopping abruptly," she explains.

Can Lash Serums Cause Lash Loss?

"Some lash serums, particularly those containing prostaglandins or related actives, can cause mild temporary shedding when first introduced, as older resting hairs are replaced by new growth. However, irritation or sensitivity to ingredients may also lead to temporary lash loss, so treatment should be discontinued if redness, irritation or discomfort develops around the eyes," says Dr Wong.

Why Trust Us

At Who What Wear UK, we know that beauty isn’t one-size-fits-all. Our editors have tested thousands of products, including skincare, makeup, hair and nails, over the years and work closely with trusted experts—dermatologists, make-up artists and leading industry insiders—to ensure every guide is well-researched, inclusive and relevant to you.

We focus on formulas that deliver, whether they’re affordable favourites or luxury investments. Our product selection is based on tangible results, ingredient know-how and what we’d truly recommend to a friend.